摘要
通过平面断裂韧度实验对紧凑拉伸(CT)试样的力学性能进行研究,分析了尖裂纹和钝裂纹试样的断裂形貌特征,并定量分析了裂纹尖端钝化对力学性能的影响。实验结果表明,尖裂纹计算得出的断裂韧度值、最大断裂值、塑性分量和最大位移量都小于钝裂纹对应的数值,裂纹尖端形成的钝化区有利于抑制裂纹扩展,提高了抵抗断裂的能力,能够达到止裂的目的。随着裂纹尖端曲率半径的不断增加,存在最佳钝裂纹曲率半径。当曲率半径超过其值,刚度出现轻微退化,塑性分量在外加载荷输入能量中所占的比重越来越大,断裂韧度提升明显,增强了试样的承载能力。研究结果可为定量评价裂纹尖端钝化对力学性能的影响提供科学依据。
Mechanical properties of compact tensile( CT) specimens were studied by plane fracture toughness test,fracture morphology characteristics of both tip crack and blunt crack specimens were analyzed,and the influence of crack tip blunting on mechanical properties was quantitatively analyzed. The experimental results show that the fracture toughness value,the maximum fracture value,the plastic component and the maximum displacement calculated by the tip crack are all smaller than the corresponding values of the blunting crack. The blunting zone formed at the crack tip is conducive to inhibiting crack propagation and improving the ability to resist fracture,which can achieve the purpose of crack arrest. With the increasing of the curvature radius of the crack tip,there is an optimal blunt crack curvature radius. When the radius of curvature exceeds its value,the stiffness slightly degrades,and the proportion of the plastic component in the input energy of the external load increases. The fracture toughness is significantly improved,which enhances the bearing capacity of the specimen. The results can provide scientific basis for quantitative evaluation of the influence of blunting crack tip on mechanical properties.
作者
张朱武
许承伟
李炜
郭丽萍
潘光国
ZHANG ZhuWu;XU ChengWei;LI Wei;GUO LiPing;PAN GuangGuo(College of Chemical Engineering,Fuzhou University,Fuzhou 350108,China)
出处
《机械强度》
CAS
CSCD
北大核心
2021年第3期531-537,共7页
Journal of Mechanical Strength
基金
国家自然科学基金项目(51705077)
福建省自然科学基金项目(2018J01768)
福州大学贵重仪器设备开放测试基金(2019T028)资助。
关键词
钝裂纹止裂
塑性分量
断裂韧度
力学性能
Blunting crackarrest
Plastic component
Fracture toughness
Mechanical properties
